John Emil List was born on September 17, 1925, in Bay City, Michigan. He was the only child of John Frederick List and Alma Barbara Florence List, who were German American. His father was very religious and a Sunday school teacher. John grew up in a devout Lutheran household, where faith played an important role in his upbringing.

John graduated from Bay City Central High School in 1943. That same year, he enlisted in the United States Army. During World War II, he served as a laboratory technician. His father passed away in 1944 while John was in the military. After being discharged in 1946, John attended the University of Michigan in Ann Arbor. He earned a bachelor's degree in business administration and a master's degree in accounting. Through the ROTC program, he was commissioned as a lieutenant.

In November 1950, as the Korean War began, List was recalled to military service. While stationed at Fort Eustis in Virginia, he met Helen Morris Taylor, who was a widow with a daughter named Brenda. John and Helen got married on December 1, 1951, in Baltimore, Maryland. After their marriage, the family moved to northern California, where List was assigned to the Finance Corps because of his accounting skills.

After completing his second military tour in 1952, List began working for an accounting firm in Detroit. He later became an audit supervisor for a paper company in Kalamazoo, Michigan, where his three children were born. By 1959, he had advanced to general supervisor of the accounting department at that company.

List’s family life faced challenges when Helen struggled with alcohol addiction and health issues due to syphilis from her first marriage. In 1960, after his stepdaughter Brenda married, List moved his family to Rochester, New York, to work at Xerox. Eventually, he became the director of accounting services there.

In 1965, List accepted a new job as vice president and comptroller at a bank in Jersey City, New Jersey. He moved his family, including his wife, children, and mother, into a large Victorian house called Breeze Knoll in Westfield, New Jersey.

On November 9, 1971, John Emil List killed five members of his family in their home in Westfield, New Jersey. He started by shooting his wife, Helen, in the back of the head. Afterward, he shot his 84-year-old mother, Alma, above the left eye. Later that day, as his children returned home from school, he murdered his daughter Patricia, who was 16, and his son Frederick, who was 13, both with a shot to the back of the head. His teenage son John Frederick, age 15, was shot repeatedly after List drove him home from a soccer game.

List placed the bodies of his wife and children on sleeping bags in the mansion's ballroom. He left his mother's body in the attic apartment. After committing the murders, he wrote a letter to his pastor, claiming he killed his family to save their souls. He cleaned the crime scenes, removed his picture from family photographs, and left the radio playing hymns. He stopped deliveries of milk, mail, and newspapers, and sent notes to schools saying the children were visiting their grandmother.

The murders went unnoticed until December 7, 1971, nearly a month later. Neighbors called the police when they noticed the house’s lights were on all the time, but no activity was observed. Officers entered through an unlocked basement window and discovered the bodies.

A nationwide manhunt began as List had disappeared. His family car was found at an airport, but he was not found on any flights. The house where the murders took place was empty until it burned down in August 1972. The fire was ruled arson and remains unsolved.

In 1972, List traveled by train across the country. He eventually settled in Denver, Colorado, under the name Robert Peter "Bob" Clark. He found work as an accountant and started a new life, even remarrying in 1985.

After the case was featured on the television show "America's Most Wanted" in 1989, he was recognized and arrested in Virginia. He was extradited back to New Jersey, where he faced trial for the murders. During the trial, he claimed financial troubles and family issues drove him to commit the murders, believing it would save their souls.

On April 12, 1990, List was convicted of five counts of first-degree murder and received a sentence of five consecutive life terms in prison. He appealed his sentence, but his arguments were rejected. He later expressed some remorse for his actions. List died in prison on March 21, 2008, at the age of 82, from pneumonia.